#nullable disable
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace System.Reflection
{
	internal struct MonoEventInfo
	{
		public Type declaring_type;
		public Type reflected_type;
		public String name;
		public MethodInfo add_method;
		public MethodInfo remove_method;
		public MethodInfo raise_method;
		public EventAttributes attrs;
		public MethodInfo[] other_methods;
	}

	[StructLayout (LayoutKind.Sequential)]
	internal sealed class RuntimeEventInfo : EventInfo
	{
#pragma warning disable 169
		IntPtr klass;
		IntPtr handle;
#pragma warning restore 169

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		static extern void get_event_info (RuntimeEventInfo ev, out MonoEventInfo info);

		internal static MonoEventInfo GetEventInfo (RuntimeEventInfo ev)
		{
			MonoEventInfo mei;
			get_event_info (ev, out mei);
			return mei;
		}

		public override Module Module {
			get {
				return GetRuntimeModule ();
			}
		}

		internal BindingFlags BindingFlags {
			get {
				return GetBindingFlags ();
			}
		}

		internal RuntimeType GetDeclaringTypeInternal ()
		{
			return (RuntimeType) DeclaringType;
		}

		RuntimeType ReflectedTypeInternal {
			get {
				return (RuntimeType) ReflectedType;
			}
		}

		internal RuntimeModule GetRuntimeModule ()
		{
			return GetDeclaringTypeInternal ().GetRuntimeModule ();
		}

		internal BindingFlags GetBindingFlags ()
		{
			MonoEventInfo info = GetEventInfo (this);

			MethodInfo method = info.add_method;
			if (method == null)
				method = info.remove_method;
			if (method == null)
				method = info.raise_method;

			return RuntimeType.FilterPreCalculate (method != null && method.IsPublic, GetDeclaringTypeInternal () != ReflectedType , method != null && method.IsStatic);
		}

        public override EventAttributes Attributes {
			get {
				return GetEventInfo (this).attrs;
			}
		}

		public override MethodInfo GetAddMethod (bool nonPublic)
		{
			MonoEventInfo info = GetEventInfo (this);
			if (nonPublic || (info.add_method != null && info.add_method.IsPublic))
				return info.add_method;
			return null;
		}

		public override MethodInfo GetRaiseMethod (bool nonPublic)
		{
			MonoEventInfo info = GetEventInfo (this);
			if (nonPublic || (info.raise_method != null && info.raise_method.IsPublic))
				return info.raise_method;
			return null;
		}

		public override MethodInfo GetRemoveMethod (bool nonPublic)
		{
			MonoEventInfo info = GetEventInfo (this);
			if (nonPublic || (info.remove_method != null && info.remove_method.IsPublic))
				return info.remove_method;
			return null;
		}

		public override MethodInfo[] GetOtherMethods (bool nonPublic)
		{
			MonoEventInfo info = GetEventInfo (this);
			if (nonPublic)
				return info.other_methods;
			int num_public = 0;
			foreach (MethodInfo m in info.other_methods) {
				if (m.IsPublic)
					num_public++;
			}
			if (num_public == info.other_methods.Length)
				return info.other_methods;
			MethodInfo[] res = new MethodInfo [num_public];
			num_public = 0;
			foreach (MethodInfo m in info.other_methods) {
				if (m.IsPublic)
					res [num_public++] = m;
			}
			return res;
		}

		public override Type DeclaringType {
			get {
				return GetEventInfo (this).declaring_type;
			}
		}

		public override Type ReflectedType {
			get {
				return GetEventInfo (this).reflected_type;
			}
		}

		public override string Name {
			get {
				return GetEventInfo (this).name;
			}
		}

		public override string ToString ()
		{
			return EventHandlerType + " " + Name;
		}

		public override bool IsDefined (Type attributeType, bool inherit)
		{
			return MonoCustomAttrs.IsDefined (this, attributeType, inherit);
		}

		public override object[] GetCustomAttributes( bool inherit)
		{
			return MonoCustomAttrs.GetCustomAttributes (this, inherit);
		}

		public override object[] GetCustomAttributes( Type attributeType, bool inherit)
		{
			return MonoCustomAttrs.GetCustomAttributes (this, attributeType, inherit);
		}

		public override IList<CustomAttributeData> GetCustomAttributesData () {
			return CustomAttributeData.GetCustomAttributes (this);
		}

		public override int MetadataToken {
			get {
				return get_metadata_token (this);
			}
		}

		public sealed override bool HasSameMetadataDefinitionAs (MemberInfo other) => HasSameMetadataDefinitionAsCore<RuntimeEventInfo> (other);

		[MethodImplAttribute(MethodImplOptions.InternalCall)]
		internal static extern int get_metadata_token (RuntimeEventInfo monoEvent);

		[MethodImplAttribute (MethodImplOptions.InternalCall)]
		static extern EventInfo internal_from_handle_type (IntPtr event_handle, IntPtr type_handle);

		internal static EventInfo GetEventFromHandle (Mono.RuntimeEventHandle handle, RuntimeTypeHandle reflectedType)
		{
			if (handle.Value == IntPtr.Zero)
				throw new ArgumentException ("The handle is invalid.");
			EventInfo ei = internal_from_handle_type (handle.Value, reflectedType.Value);
			if (ei == null)
				throw new ArgumentException ("The event handle and the type handle are incompatible.");
			return ei;
		}
	}
}